This article provides a critical introduction to an issue fo Ratio Juris concerend with two contrasting schools of legal idealism: the so-called
Sheffield School (Beyleveld, Brownsword and colleagues) and the “discourse ethics” school of Habermas and Alexy. The article focusses on four issues: (1) whether a "claim to correctness" is a necessary feature of law, (2) the connection between correctness and validity, (3) Alexy's argument for a "qualifying connection" between law and morality, and its counterpart in the Sheffield School's approach, and (4) Alexy's case for the "Radbruch formula": that "extreme injustice is not law”. While rejecting both versions of the case for legal idealism, I argue that both schools offer vaulable, and broadly similar, insights into what makes a legal system morally legitimate.